1. Field of the Invention
The present invention relates to the manufacture of a multilayer metal thin film in a semiconductor manufacturing process, and more particularly, to a method and apparatus for manufacturing a multilayer metal thin film without additional heat treatment processes.
2. Description of the Related Art
As a representative example of a multiplayer metal thin film, there is a cobalt/titanium/titanium nitride (Co/Ti/TiN) layer. The Co/Ti/TiN layer has been widely used to decrease contact resistance between a source/drain region and a gate as a metal oxide semiconductor (MOS) device is miniaturized on a scale of tens of nanometers or less. Here, in general, a Co layer, a Ti layer, and a TiN layer are formed at different reaction containers from each other, and after the Co layer is deposited, in order to decrease contact resistance, carbon included in the Co layer is removed by performing heat treatment or plasma processing.
FIG. 1 is a view illustrating a conventional example of a method of manufacturing a Co/Ti/TiN layer. FIG. 2 is a view illustrating an example of an apparatus 200 for manufacturing the Co/Ti/TiN layer illustrated in FIG. 1.
Referring to FIGS. 1 and 2, conventionally, Co is deposited on a silicon substrate in a first reaction container 210 in a chemical vapor deposition (CVD) process to form a Co layer (step S110), and heat treatment or plasma processing is performed in a second reaction container 220 to decrease resistance of the Co layer (step S120). Thereafter, Ti is deposited in a third reaction container 230 to form a Ti layer (step S130), and a TiN layer is formed in a fourth reaction container 240 (step S140).
However, in the aforementioned method, after the Co layer is formed in the first reaction container 210 in the CVD process, the second reaction container 220 is needed to perform the heat treatment or plasma processing. In addition, when a wafer is transferred to the third reaction container 230 after the heat treatment or plasma processing is performed, the wafer is exposed to the air and a natural oxide layer is formed thereon, and this causes increase in the contact resistance. In addition, in order to form the Co/Ti/TiN layer, the four reaction containers are needed. Accordingly, there is a problem in that productivity of the Co/Ti/TiN layer may be decreased.
In order to solve the aforementioned problem, recently, the heat treatment or plasma processing performed in the second reaction container 220 and forming the Ti layer performed in the third reaction container 230 are performed in a single reaction container. Specifically, in the single reaction container, the Co layer is heat-treated, and the Ti layer is then formed. However, in this method, the heat treatment of the Co layer and the formation of the Ti layer are separately performed, so that there is a problem in that forming the Co/Ti/TiN layer still requires much time.